Flares affect many heights throughout the solar atmosphere. According to the standard flare model [1]}, [2]}, they are initiated by the reconnection of field lines in the corona, where magnetic energy is converted into kinetic energy through the acceleration of particles, both towards the lower solar atmosphere and into space. As the accelerated particles precipitate through denser atmospheric layers towards the solar surface, they lose their energy via several mechanisms, with a significant fraction of this energy being converted into radiation, heat, and bulk particle motions. Many spectral lines respond to the evolving atmosphere by changing their shapes, intensities, and Doppler shifts.
